2015-02-04T17:45:14+00:00http://www.archaeogeek.com/Octopress2014-11-30T08:00:00+00:00http://www.archaeogeek.com/blog/2014/11/30/postgis-day-2014On 20th November this year we held the first PostGIS “Show-and-Tell” Day at the HQ of the British Computing Society. This was the first “official” OSGeo:UK event since hosting FOSS4G 2013 in Nottingham last year- it took us that long to recover from the stress!

We deliberately chose to make the event extremely light and informal, with the minimum of organisation, and this seemed to work pretty well. We had a range of speakers doing both longer talks and lightning talks, and then a session at the end where we discussed useful tools and add-ons for working with PostGIS.

The only caveats we placed on speakers were that the talk should (obviously) include PostGIS or PostgreSQL in some way, and that overt sales pitches would be considered uncool. Luckily our speakers obliged! There was also some really good audience interaction.

Highlights for me included Foreign Data Wrappers, for getting at information stored in other databases or behind other apis, but through PostgreSQL, and Raster processing. I was particularly excited by the Twitter FDW, but it turns out that it doesn’t work with the latest version of the twitter api, and it doesn’t look like a particularly well-maintained piece of code. You can see links to all the talks, and notes from the discussion that we had at the end, at our OSGeo:UK GitHub repository for the event: http://osgeouk.github.io/pgday/.

It transpired that there were a number of other events globally, also celebrating #PostGISDay, and perhaps next year it would be good to coordinate these better.

From an OSGeo:UK perspective, we have plans to hold more of these light-touch events, on a range of subjects (ideas gratefully received). Personally I would like to have charged a nominal fee for attending the event, not to make a profit but so that we could make a small donation back to PostGIS but charging money makes the whole process more complicated! We were extremely lucky in this case to get the venue for free, courtesy of the BCS Location Information Group, and to get the food sponsored by Astun Technology.

All in all, a really fun event, both to organise and to attend- thanks to all the speakers and attendees, and here’s to another event quite soon.

]]>2014-09-25T09:49:00+01:00http://www.archaeogeek.com/blog/2014/09/25/new-portable-gis-releasesI’m pleased to announce not one, but two new releases of Portable GIS! The first, version 4.2, contains QGIS 2.4 and PostGIS 1.5 and will be the last release to include that version of PostGIS.

The second, version 5, contains QGIS 2.4 and PostGIS 2.1 and all future releases will be based on this. Get them here:

There are two important things about these two releases. The first is that the download size is almost twice what it was previously- this is out of my control and is due to the increased size of the QGIS installation. The second is that version 5.0 should be considered a beta release as it’s very much un-tested. If there are any problems let me know via the Portable GIS google group.

]]>2014-01-20T10:40:00+00:00http://www.archaeogeek.com/blog/2014/01/20/portable-gis-v4Here’s a quick and overdue announcement to say that I’m making a new version of Portable GIS available today, including QGIS 2. Consider this one a beta release, since I really want to upgrade PostGIS and GDAL when I get time. Additional upgrades in this version: Astun Technology’s Loader has been upgraded to the latest version, and Psycopg2 is now included.

Before you click on the link, please take time to read the main Portable GIS page, and also do me the favour of reporting any problems that you find at the portable GIS google group, or via Twitter. If you can provide me with a screenshot of an error, and let me know the exact version of Windows that you’re using, then I’ll do my best to fix.

You can pick up the beta version here. This is a dropbox link, so if it’s not available, then I’ve exceeded my bandwidth for the moment, so please try again later.

I hope to get a release out fairly soon with PostGIS 2.1 and GDAL 1.10, but this is not my day job so bear with me!

]]>2012-08-13T16:30:00+01:00http://www.archaeogeek.com/blog/2012/08/13/postgis-for-beginnersUPDATE: Shortly after submitting this post, up popped another from Paul Ramsey that does a really good job of explaining why things are done they way they are. I recommend you read it!

Via Paul Ramsey, this post popped onto my radar the other day and got me thinking. My initial impressions about the post were quite negative, and to be honest some of the points still mystify me, but after further investigation, at least some of the issues do make sense, so perhaps there is some room for improvement in our favourite spatial database. If you haven’t read it, do that and come back. I’ll wait…

Let’s take the first statement- that PostGIS can be “mind-numbingly difficult to install and use”. The author of the post is mainly talking about Ubuntu servers, so I think it would be fair to assume some level of IT literacy here. If you go off and do a web search for “Ubuntu PostGIS”, which these days is likely to be the new user’s first port of call, then for me at least the first few links are generally to old blog posts explaining, often with long lists of commands, how to install on say, Ubuntu 7.10 or 8.04, and then there’s some posts about compiling it from source with the latest version of PostGIS. There are some links to information about modern versions of Ubuntu as well, but they are not top of the list. Most links also say to add another ppa to your list of repositories, which is fairly standard for Linux but if you approach this with a new-user mindset then it’s not very reassuring. So I went looking to see if PostGIS was in the official Ubuntu repositories, and it is- but you’d have to go looking to find it. So, I wouldn’t go as far as saying mind-numbingly difficult, but as a new user you could end up making things a lot more complicated than they need to be. I’m not sure what the solution is though- manipulate google search results so that the official Ubuntu repositories appear at the top?

Buried amongst this discussion is a point about back-porting fixes or patches to prior stable releases. This might happen, and I can see a scenario where it could be a pain for a system maintainer, but since when was this a problem just with PostGIS, or FOSS in general? It’s just as prevalent, if not worse, in the proprietary software world.

Onto import and export. I tend to agree here, up to a point, that trying to use shp2pgsql at the command line as a new user is not easy. However, every time I’ve done an install recently, I’ve been asked whether I want to include the shp2pgsql loader for PgAdmin, or indeed I’ve just gone with the import tool that comes with QGIS. So using the command line for a simple import and export is not really necessary at all. Anyway, yes, please get the srid right rather than auto-populating it with -1, and please use the (sanitised) shape file name as the default table name. Yes, make it easier to get a csv file with an easting and a northing in it, rather than making users go to ogr2ogr and learn another command line syntax.

However, we then get on to the section that I most vehemently disagree with. The general premise seems to be that the end user should not worry their pretty little head about the database they are importing into, or the user that they are using to do it, or the spatial reference system that the data comes with. Automating all of these processes might make it easier for the end user, but at the expense of them actually understanding what they are doing. The minute that this clever automated process fails, or puts the data somewhere you didn’t expect, then you can be sure that a lot of end users will decide that “open source is rubbish, where’s my ArcGIS”. Been there, seen that. Teaching people to press buttons without thinking leads to rubbish output- be that in open source, proprietary, gis, or any other software.

Forward-compatibility of backups. I’m such a fan of the inherent future-proofing and openness of a plain-text SQL dump, and I’ve never hit an issue with upgrades if I follow the instructions, so this surprised me. However, trying to come at this from a new user’s perspective, sometimes it’s not straightforward. However, progress and improvement of software means it’s not always possible to totally guarantee compatibility between versions. Again, this is not the sole province of open source- how many times have you had issues with a doc to docx conversion in Microsoft Office, for example? (Answer- many)

Geometry invalidity- yes, I see this all the time. Client sends data in mapinfo or shape format. We load it into PostgreSQL, it croaks. Sometimes the “really small buffer” trick, or similar, works, sometimes we have to go back to the client to ask them to resolve the issue. Again, I would rather do this, and enforce ideas of data validity and quality, rather than dumb things down so we never have to think about what we’re doing.

Finally, it’s worth remembering that PostGIS is a spatial extension, it’s not a program in it’s own right. Comparing it to Arc Toolbox is like comparing a car engine with a complete car. Amazingly, the whole article was written without a single mention of PgAdmin, or QGIS, or any other interface that will work with PostGIS, and provide users with a lot of the bells and whistles that the author is asking for.

In conclusion- I reluctantly find that I agree with the points around installation. It could be easier- at least to find documentation. Import into postgresql could be easier, or you can use QGIS. But please, don’t make it so easy that users don’t have to think!

]]>2012-07-06T17:14:00+01:00http://www.archaeogeek.com/blog/2012/07/06/agi-north-conferenceOn Wednesday I presented at a great conference in Manchester, organised by the AGI Northern Group, entitled “Innovation and Value in Geographic Information”. The presentations covered a wide range of subjects, and to be honest a few were barely “GI”, but I really enjoyed them, so there! You can find all the talks here.

The stand-out presentations for me were probably Gary Gale’s, which was hardly about “GI” at all (unless you count FourSquare, which I don’t) but was about archiving our personal data from Flickr, Twitter, Facebook et al, and Bob Barr’s, which was about the bonkers situation that is Addressing in the UK. Bob, as usual, had everyone in fits of laughter, which is impressive when talking about such a dry subject.

My own talk was entitled “Consuming linked and open data with open source tools, or: actually doing something useful with all of this free stuff”. You can find it on slideshare here. It was really meant to be a live demo, but it’s impossible to be sure you can connect your linux laptop to projectors at these places and get a link out to the internet, so I chickened out. This talk was, though, the first public outing for a couple of python scripts I have been working on, to download open data via the police.uk api and linked transport data from naptan. When I’m feeling brave, I will be putting the scripts on the Astun Github Site but not just yet.

All in all, an enjoyable day- so thanks to the AGI Northern Group for inviting me along!